Two-Dimensional Second-Order Topological Insulator in Graphdiyne
Two-Dimensional Second-Order Topological Insulator in Graphdiyne
复制标题
石墨炔中的二维二阶拓扑绝缘体
DOI：
10.1103/physrevlett.123.256402
复制
发表时间：
2019-12-18
影响因子：
8.6
通讯作者：
Yang, Shengyuan A.
中科院分区：
文献类型：
--
作者：
Sheng, Xian-Lei;Chen, Cong;Yang, Shengyuan A.
d空间维度的二阶拓扑绝缘体（SOTI）在两个晶面相交处的（d - 2）维边界处具有拓扑保护的无带隙态，但在其他方面则有带隙。作为一种新的拓扑状态，它已经引起了人们极大的兴趣，但它仍然是一个挑战，以确定一个现实的SOTI材料在二维（2D）。在这里，结合第一性原理计算和理论分析的基础上，我们揭示了已经实验合成的2D材料graphdiyne作为2D SOTI的第一个现实的例子，具有拓扑保护的0 D角状态。晶体对称性的作用，对对称性破缺的鲁棒性，和可能的实验表征进行了讨论。我们的研究结果揭示了一个隐藏的graphdiyne的拓扑特征，并促进它作为一个具体的材料平台，探索有趣的物理学高阶拓扑相。
A second-order topological insulator (SOTI) in d spatial dimensions features topologically protected gapless states at its (d - 2)-dimensional boundary at the intersection of two crystal faces, but is gapped otherwise. As a novel topological state, it has been attracting great interest, but it remains a challenge to identify a realistic SOTI material in two dimensions (2D). Here, based on combined first-principles calculations and theoretical analysis, we reveal the already experimentally synthesized 2D material graphdiyne as the first realistic example of a 2D SOTI, with topologically protected 0D corner states. The role of crystalline symmetry, the robustness against symmetry breaking, and the possible experimental characterization are discussed. Our results uncover a hidden topological character of graphdiyne and promote it as a concrete material platform for exploring the intriguing physics of higher-order topological phases.